CN105524203B - A kind of method that EVA elastomers are prepared using mixed solvent - Google Patents
A kind of method that EVA elastomers are prepared using mixed solvent Download PDFInfo
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- CN105524203B CN105524203B CN201410509415.1A CN201410509415A CN105524203B CN 105524203 B CN105524203 B CN 105524203B CN 201410509415 A CN201410509415 A CN 201410509415A CN 105524203 B CN105524203 B CN 105524203B
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Abstract
The present invention relates to a kind of method that EVA elastomers are prepared using mixed solvent, it is included in the presence of the mixed solvent being made up of methanol and the tert-butyl alcohol, ethene is carried out copolyreaction with vinyl acetate.The present invention is on the basis of original EVA solution polymerization process, mixed by different proportion solvent, the VAc contents brought using single solvent can be avoided relatively low and the problems such as raw material production cost is too high while high Copolycondensation rate and high solids content is ensured, there is certain industrial application value.
Description
Technical field
The present invention relates to a kind of method that EVA elastomers are prepared using mixed solvent, belong to solution polymerization field.
Background technology
Vinyl-vinyl acetate copolymer (EVA) is at present in the world after polyethylene from high pressure process (LDPE), low-pressure polyethylene
(HDPE), the fourth-largest ethene copolymer after LLDPE (LLDPE).EVA is by nonpolarity, crystallization sex ethylene
Monomer (E) and amorphism vinyl acetate (VAc) monomer trigger copolymerization to obtain by radical polymerization system.EVA is similar
In the thermoplastic of elastomer rubber, the VAc contents of its performance and copolymerization system are closely related.The EVA products of low VAc contents
Performance is similar with LDPE；High VAc contents EVA products, its performance are infinitely close to rubber elastomer.EVA have excellent elasticity,
Pliability, the transparency, tackness, cold flexibility, stress cracking resistance, resistance to corrosive chemicals and with filler color masterbatch phase
Capacitive, combination property are better than conventional polyethylene (PE) product.The series of formed processing such as can be foamed, be blow molded, it can also be used to
Polyethylene (PE), polyvinyl chloride (PVC) and the enhancing of industrial rubber articles blending toughening are modified, and are widely used in agricultural film, shoemaking, electricity
Cable, field of solar energy.
Patent US 2396785A describe ethene and vinyl acetate and leave the molten of progress in radical initiator and solvent
Liquid polymerization process.This reaction is reacted for gas-liquid two-phase solution copolymerization.Benzoyl peroxide is initiator, and isooctane is solvent, 75
~77 DEG C of initiations polymerize, and VAc contents only have 10wt% in product；Patent US 2947735 is molten to mix from the tert-butyl alcohol and water
Agent, 63 DEG C are triggered polymerization, and a small amount of water is added in polymerization system, and regulation solution ph improves decomposition of initiator effect between 3~7
Rate, increase substantially product solid content.But the method only prepares 15~35wt% of VAc contents low VAc contents EVA resin
Product, though VAc contents are slightly lifted, and it is incompetent for the EVA elastomer products of more preferable, the higher VAc contents of production performance, this method
For power.
Patent US 3115485A describe adds the mixed solvents such as iso-butane/isooctane progress EVA in solvent tertiary butanol
Prepare.The EVA yields and mechanical property of this method production are obviously improved, but VAc contents only have 19wt% or so, greatly limit production
The ease for use and application prospect of product.In patent US 3159608A, Exxon companies use benzene and toluene as mixed solvent, ethene and
Vinyl acetate free radical trigger polymerisation in solution, 137~171 DEG C of polymerization temperature, before unreacted in solvent VAc concentration be 0.2~
10wt%, product VAc content are 15~28wt%, and target product VAc contents are still relatively low, and mixed solvent system selection is improper.
Patent US 3325460A describe removes heat problem to solve reaction, using multi-floating bodies EVA preparation technologies.This
The process selection tert-butyl alcohol is solvent, and peroxide initiation systems, 20~120 DEG C are triggered polymerization.This technique is only had from the tert-butyl alcohol
Beneficial to product Mooney viscosity is reduced, product VAc contents are greatly improved to 40~75wt%；US 5576401A are described using six
Reactor is connected, and the tert-butyl alcohol is solvent, and 62~70 DEG C of initiations polymerize, product VAc content 60wt%, and properties of product are excellent.
Patent CN1179989C, which is described, uses EVA free radical polymerization process of the methanol for solvent, and ethylene pressure 20~
60bar, 55~75 DEG C of initiation polymerizations, product VAc content 30-40wt% are slightly below simple to make solvent preparation institute from the tert-butyl alcohol
Obtain EVA products.Methanol, which makees solvent, can substantially reduce acetaldehyde in system VAc, while low boiling methanol as solvent is also easy to
Purification of products and solvent recovery and post processing, low-viscosity polymerization system remove heat conveniently, and industrial energy saving consumption reduction value is notable.
The content of the invention
The invention provides a kind of method that EVA elastomers are prepared using mixed solvent, by adjust in solvent methanol and
The amount ratio of the tert-butyl alcohol, molecular weight and the controllable EVA elastomers of molecular weight distribution can be prepared under radical polymerization system.
To achieve the above object, method of the invention includes：
In the presence of solvent, ethene is made to carry out copolyreaction with vinyl acetate.Unlike the prior art, it is of the invention
In solvent for methanol and the tert-butyl alcohol mixed solvent.
In one embodiment of the invention, the volume ratio of the methanol and the tert-butyl alcohol is 1:100~100:1.
In a preferred embodiment of the invention, the volume ratio of the methanol and the tert-butyl alcohol is 20:80~80:20,
VAc content is 70~76wt% in obtained EVA products.
In the most preferred embodiment of the present invention, the volume ratio of the methanol and the tert-butyl alcohol is 20:80, what is obtained
VAc content is 76wt% in EVA products.
Applicants have discovered that when the tert-butyl alcohol is higher in the mixed solvent dosage, VAc content is also higher in EVA products,
The performance of product elastomeric characteristic is more obvious.But meanwhile in the mixed solvent tert-butyl alcohol used in amounts will control within the specific limits, tertiary fourth
Alcohol ratio exceedes certain limit, and VAc contents in product EVA can be caused to reduce.
What the hybrid mode of methanol and the tert-butyl alcohol can be known in the art is stirred.Due to the boiling of methanol at ambient pressure
(64.5 DEG C) of point is less than the tert-butyl alcohol (82.5 DEG C), to be more fully mixed two kinds of solvents, first by second preferably before copolyreaction
Vinyl acetate is mixed with the tert-butyl alcohol, and methanol is pressed into the mixed of vinyl acetate and the tert-butyl alcohol by compressed air in an inert atmosphere
Close in liquid, ethene is carried out copolyreaction with vinyl acetate.
Need to add initiator before copolyreaction, conventional initiator includes azo and/or peroxidating class compound, example
Such as azodiisobutyronitrile, ABVN, cumyl hydroperoxide, dibenzoyl peroxide.Initiator amount is acetic acid
The 1-5wt% of vinyl acetate monomer dosage.More than above range, initiator amount increase can improve polymerization rate, but simultaneously
The increase of system viscosity, is unfavorable for being carried out continuously for production.
The reaction condition that the copolyreaction of the present invention is conventional is：Temperature is 40-125 DEG C, ethylene pressure 2-9MPa, the time
For 2-10 hours.
The copolyreaction device for the above method of the present invention includes：
Copolyreaction kettle, for solution copolymerization reaction to occur and provides reacting environment for vinyl acetate and ethene；With
Rabbling mechanism, for realizing the raw material mixing inside copolyreaction kettle.
In one embodiment of the invention, the copolyreaction kettle top is provided with mixed solvent and vinyl acetate liquid phase
Charging aperture, and ethylene feed, bottom are provided with discharging opening.
In one embodiment of the invention, the rabbling mechanism is located at copolyreaction kettle axis line inside position, by according to
Drive device, transmission device, agitating shaft and the agitating paddle composition of secondary connection.Anchor formula oar, ribbon oar, whirlpool can be used in the agitating paddle
The combination of wheeled agitating paddle or anchor formula oar and vane wheel oar.
In one particular embodiment of the present invention, agitating shaft is longitudinally provided with copolyreaction kettle center, and stirred
Axle is provided with blade, and the motor on the upside of kettle drives agitating shaft to rotate by transmission mechanism.Kettle lower end is provided with end socket simultaneously
Discharging opening is left in end socket bottom.By mixed solvent out of liquid phase feeding mouth injection kettle, vinyl acetate is added after logical nitrogen deoxygenation
Ester and ethene carry out polymerisation, and one-pot or multi-floating bodies technique can be selected.
Based on above-mentioned copolyreaction device, in a preferred embodiment of the invention, EVA bullets are prepared using mixed solvent
The method of property body, which is included in before copolyreaction, first mixes vinyl acetate with the tert-butyl alcohol, passes through 5~8MKPa in an inert atmosphere
Compressed air methanol is pressed into the mixed liquor of vinyl acetate and the tert-butyl alcohol, then by ethene, initiator, vinyl acetate
Be continuously introduced into copolyreaction kettle and reacted with mixed solvent, and by copolyreaction product from foregoing copolyreaction kettle it is continuous
Export, carries out later separation and the processing of product.
The present invention can also add other polymerized monomers while EVA polymerize and is copolymerized.As what is used in copolymerization
Polymerized monomer can enumerate the alkene such as propylene, n-butene, isobutene, 1- hexenes, 1- octenes.The addition selection of these polymerized monomers
In the range of not hindering the present invention to realize goal of the invention.
This area generally believes (as described in patent CN1179989C) that it is C4 that EVA solution, which polymerize usually used solvent,
Following fatty alcohol.If use fatty alcohol or aromatic alcohol of the carbon number more than 5, it is impossible to give full play to effect.As C4
Following fatty alcohol can enumerate methanol, ethanol, propyl alcohol, butanol etc., and obtained EVA elastomer performances are excellent.Low boiling simultaneously
Solvent (such as from methanol) is also easy to purification of products and solvent recovery and post processing, and industrial energy saving consumption reduction is notable.The tert-butyl alcohol is certainly
Body has certain viscosity, and chain transfer constant is relatively low, is advantageous to be copolymerized macromolecular chain growth.If two kinds of solvents are used in mixed way,
Amount ratio by changing methanol and the tert-butyl alcohol can be realized to EVA copolymer molecular weight and molecular weight distribution regulation and control, ensured
System viscosity can be adjusted while Copolycondensation rate, prepares the EVA elastomers for meeting different needs.
The present invention is mixed on the basis of original EVA solution polymerization process by different proportion solvent, can ensure height
While Copolycondensation rate and high solids content, avoid the VAc contents brought using single solvent relatively low and raw material production cost
The problems such as too high；Simultaneously by changing the volume ratio of solvent methanol/tert-butyl alcohol, in obtained EVA products VAc contents realize
It is regular controllable, the EVA elastomer products for meeting different production and living needs can be prepared, there is certain industrial application value.
Brief description of the drawings
Fig. 1 is the ethylene-vinyl acetate c reaction unit schematic diagram of the present invention, is illustrated by taking one-pot technique as an example.
In figure：1- copolyreaction kettles；2- stirring motors；3- agitating shafts and agitating paddle；4- liquid phase feeding mouths；5- ethylene feeds
Mouthful；6- discharging openings.
Embodiment
The present invention is further explained below by embodiment.
The copolyreaction device that EVA elastomers are prepared using mixed solvent as shown in Figure 1.Using one-pot intermittently operated,
Including copolyreaction kettle 1 and rabbling mechanism.The rabbling mechanism includes stirring motor 2, transmission device (not shown) and stirred
Mix axle and the agitating paddle being fixed on agitating shaft 3.When reactor works, agitating paddle and part agitating shaft positioned at reaction liquid level with
Under.In process of production, solvent, vinyl acetate and initiator add copolyreaction kettle 1 from liquid phase feeding mouth 4, by ethene from
Ethylene feed 5 constantly reaches that predetermined pressure is constant in pressurization injection copolyreaction kettle 1, carried out under suitable temperature and pressure
Ethane-acetic acid ethyenyl ester solution copolymerization reacts.After reaction terminates, reaction mass is discharged from discharging opening 6.
Using the VAc contents in nuclear-magnetism, elementary analysis and infrared three kinds of methods measure product in embodiment.
Embodiment 1
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 20:80；The body of mixed solvent and vinyl acetate
Product is than being 2:1；Initiator is benzoyl peroxide, and dosage is the 0.5wt% of vinyl acetate；Polymeric reaction temperature is 85 DEG C,
Ethylene pressure is 7MPa, 4 hours reaction time.Under the conditions of this, VAc contents are 76wt% in polymerizate.
Embodiment 2
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 40:60；The body of mixed solvent and vinyl acetate
Product is than being 2:1；Initiator is benzoyl peroxide, and dosage is the 0.5wt% of vinyl acetate；Polymeric reaction temperature is 85 DEG C,
Ethylene pressure is 7MPa, 4 hours reaction time.Under the conditions of this, VAc contents are 73wt% in polymerizate.
Embodiment 3
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 60:40；The body of mixed solvent and vinyl acetate
Product is than being 2:1；Initiator is benzoyl peroxide, and dosage is the 0.5wt% of vinyl acetate；Polymeric reaction temperature is 85 DEG C,
Ethylene pressure is 7MPa, 4 hours reaction time.Under the conditions of this, VAc contents are 71wt% in polymerizate.
Embodiment 4
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 80:20；The body of mixed solvent and vinyl acetate
Product is than being 2:1；Initiator is benzoyl peroxide, and dosage is the 0.5wt% of vinyl acetate；Polymeric reaction temperature is 85 DEG C,
Ethylene pressure is 7MPa, 4 hours reaction time.Under the conditions of this, VAc contents are 70wt% in polymerizate.
Comparative example 1
Methanol tert-butyl alcohol mixed solvent is not used, single use methanol, other reaction conditions are constant, and product VAc contents are
32wt%, copolymerization product viscosity is larger, and do not demonstrate flexibility body characteristicses.
Comparative example 2
Methanol tert-butyl alcohol mixed solvent is not used, the single use tert-butyl alcohol, other reaction conditions are constant, product VAc contents
For 62wt%.
Comparative example 3
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 15:85, other reaction conditions are constant, polymerization production
VAc contents are 68wt% in thing.
Comparative example 4
Methanol and the tert-butyl alcohol are used as mixed solvent, both volume ratios are 10:90, other reaction conditions are constant, polymerization production
VAc contents are 65wt% in thing.
By the data comparison of embodiment and comparative example 1 and 2, illustrate mixing using methanol provided by the invention and the tert-butyl alcohol
Bonding solvent, in the case where other reaction conditions are constant, VAc contents significantly improve in EVA products, and show notable elasticity
Body characteristicses；By embodiment and comparative example 3 and 4 data comparisons, illustrate in the range of the mixed solvent of application claims, produce
VAc contents in thing increase with the raising of the tert-butyl alcohol, but can decline again more than this scope VAc contents.
Embodiment 5~8
Except first vinyl acetate is mixed with the tert-butyl alcohol, then in nitrogen atmosphere by 5~8MKPa compressed airs by first
Alcohol is pressed into the mixed liquor of vinyl acetate and the tert-butyl alcohol, then by the mixed of initiator, vinyl acetate, and methanol and the tert-butyl alcohol
Bonding solvent is fed outside from liquid phase feeding mouth 4, and other test parameters are corresponding with embodiment 1~4 respectively.VAc contents in polymerizate
Respectively 78wt%, 74.5wt%, 72wt%, 71wt%.Illustrate further improve using preferable solvent hybrid mode
VAc contents in polymerizate.
To sum up, the present invention is in vinyl-vinyl acetate copolymer production process, by using the mixed of methanol and the tert-butyl alcohol
Bonding solvent, can Reasonable adjustment polymerization system viscosity, improve diffuser efficiency of the free radical in high glutinous system.In guarantee system height
While Copolycondensation rate, high solids content, avoid single using VAc contents caused by homogeneous solvent are relatively low and raw material life
The problems such as cost is too high is produced, there is certain industrial application value.
It should be noted that embodiment described above is only used for explaining the present invention, do not form to any of the present invention
Limitation.By referring to exemplary embodiments, invention has been described, it should be appreciated that word wherein used is descriptive
With explanatory vocabulary, rather than limited vocabulary.The present invention can be made within the scope of the claims by regulation
Modification, and the present invention is revised in without departing substantially from scope and spirit of the present invention.Although the present invention described in it relates to
And specific method, material and embodiment, it is not intended that the present invention is limited to wherein disclosed particular case, on the contrary, this hair
It is bright to can be extended to other all methods and applications with identical function.
Claims (12)
1. a kind of method that EVA elastomers are prepared using mixed solvent, is included in the mixed solvent being made up of methanol and the tert-butyl alcohol
In the presence of, ethene is carried out copolyreaction with vinyl acetate, the volume ratio of the methanol and the tert-butyl alcohol is 10:90~80:20.
2. according to the method for claim 1, it is characterised in that the volume ratio of the methanol and the tert-butyl alcohol is 20:80~80:
20。
3. according to the method for claim 2, it is characterised in that the volume ratio of the methanol and the tert-butyl alcohol is 20:80.
4. according to the method described in any one of claims 1 to 3, it is characterised in that before copolyreaction first by vinyl acetate with
The tert-butyl alcohol mixes, and methanol is pressed into the mixed liquor of vinyl acetate and the tert-butyl alcohol by compressed air in an inert atmosphere, so
After ethene and vinyl acetate is carried out copolyreaction.
5. method according to claim 1 or 2, it is characterised in that azo and/or peroxidating are added before copolyreaction
Class compound is as initiator.
6. according to the method for claim 5, it is characterised in that it is different that the initiator is selected from azodiisobutyronitrile, azo two
At least one of heptonitrile, cumyl hydroperoxide and dibenzoyl peroxide.
7. according to the method for claim 5, it is characterised in that the initiator amount is vinyl acetate monomer dosage
1-5wt%.
8. method according to claim 1 or 2, it is characterised in that the copolyreaction condition is：Temperature is 40-125
DEG C, ethylene pressure 2-9MPa, the time is 2-10 hours.
9. method according to claim 1 or 2, it is characterised in that ethene, vinyl acetate, initiator and mixing is molten
Agent, which is continuously introduced into copolyreaction kettle, is reacted, and reaction product is continuously exported from foregoing copolyreaction kettle.
10. according to the method for claim 9, it is characterised in that other polymerized monomers are added while copolyreaction and are entered
Row copolymerization.
11. according to the method for claim 10, it is characterised in that other polymerized monomers are selected from propylene, n-butene, different
At least one of butylene, 1- hexenes and 1- octenes.
12. method according to claim 1 or 2, it is characterised in that in obtained EVA products VAc content be 70~
76wt%.
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| CN107793520B (en) * | 2016-09-07 | 2020-10-23 | 中国石油化工股份有限公司 | Method for preparing polyethylene-polyvinyl acetate elastomer soap-free microemulsion |
| CN113105574A (en) * | 2021-04-12 | 2021-07-13 | 江苏斯尔邦石化有限公司 | Ethylene-vinyl acetate copolymer and preparation method and application thereof |
| CN114230700B (en) * | 2022-01-07 | 2022-10-04 | 云南正邦科技有限公司 | Method for preparing high-ethylene-content EVA copolymer through medium and low pressure solution polymerization |
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| US3510464A (en) * | 1968-04-05 | 1970-05-05 | Kuraray Co | Process for the preparation of saponified homopolymers of vinyl acetate and copolymers and vinyl acetate |
| JP4330253B2 (en) * | 2000-06-29 | 2009-09-16 | 株式会社クラレ | Process for producing ethylene-vinyl acetate copolymer and saponified product thereof |
| TW593350B (en) * | 2000-10-18 | 2004-06-21 | Kuraray Co | The method for preparing ethylene-vinylacetate copolymer as well as the saponification substance obtained by this way and the moldings containing it |
| DE60228011D1 (en) * | 2001-03-30 | 2008-09-18 | Kuraray Co | Process for the preparation of an ethylene-vinyl acetate copolymer and apparatus for its preparation |
| CN104098731B (en) * | 2013-04-11 | 2017-05-24 | 中国石油化工集团公司 | Method for preparing ethylene-vinyl alcohol copolymer through composite initiation system |
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